JP3080802B2 - Subcooled ice thermal storage device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercooled ice heat storage device.

[0002]

2. Description of the Related Art A system diagram of a conventional supercooled ice heat storage device is shown in FIG. The high-temperature and high-pressure gas refrigerant compressed by the variable capacity compressor 2 such as a turbo refrigerator driven by the motor 1 enters the condenser 4 and radiates heat to the cooling water flowing through the heat transfer tube 4a. Condensed and liquefied. The liquid refrigerant enters the supercooling heat exchanger 3 via a refrigerant flow control device also serving as a throttle (not shown), where it is evaporated and vaporized by cooling the cold water flowing through the heat transfer tube 3a. And is compressed again.

[0003] The cooling water heated by flowing through the heat transfer tube 4a of the condenser 4 enters a cooling tower 17, where the temperature is lowered by releasing heat to the atmosphere, and the cooling water is energized by a cooling water pump 14 and again. Circulates to the condenser 4.

[0004] During the heat storage operation, the cold water of O ° C stored in the ice heat storage tank 10 is extracted by the chilled water pump 5 and enters the preheating heat exchanger 7 where it is preheated and then the bypass circuit 21.
And, it joins with the cold water flowing through the on-off valve 22 interposed therein and reaches a predetermined temperature (approximately + 0.5 ° C.). After entering the heat exchanger 3 and flowing through the heat transfer tube 3a, the heat exchanger 3 is supercooled to about -1.5 ° C. by exchanging heat with a refrigerant outside the tube.

[0005] The supercooled water passes through a cold water pipe 13 and is stored in an ice heat storage tank.
Returning to 10, the supercooled state is released, so that sherbet-shaped ice blocks 20 are generated and stored. During this time, the cold water in the return pipe 16 is extracted by the pump 31 and enters the preheating heat exchanger 7, is cooled by flowing through the heat transfer pipe 7 a, and then flows into the supply pipe 15.

The temperature of the chilled water at the outlet of the supercooling heat exchanger 3 is detected by a temperature detector 11 and input to a controller 12. The controller 12 outputs a signal to the servomotor 18 to adjust the opening of the suction vane 19 of the centrifugal chiller 2 to maintain the temperature of the chilled water at the outlet of the subcooling heat exchanger 3 at a set value.

During the cooling operation, the cold water in the ice heat storage tank 10 is extracted by the cold water pump 23 and sent to the cold demanding destination 24 such as a cooling machine through the supply pipe 15 where the temperature is raised by cooling. The cold water returns to the ice heat storage tank 10 via the return pipe 16.

[0008]

In the above-mentioned conventional apparatus,
When the opening of the suction vane 19 of the centrifugal chiller 2 is adjusted,
Since the evaporation pressure and temperature of the refrigerant in the subcooling heat exchanger 3 change rapidly, there is a possibility that the cold water freezes in the heat transfer tube 3a or the fluidity of the cold water decreases.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its gist is to provide a refrigerant with a variable capacity compressor, a condenser and a supercooling heat exchanger. While circulating in order, the cold water supplied from the ice heat storage tank through the preheating heat exchanger and its bypass circuit is cooled to the supercooled state by the supercooled heat exchanger, and then the supercooled state is released by the ice heat storage tank. In the supercooling type ice heat storage device that generates and stores ice by means of the above, a temperature detector for detecting the cold water temperature at the entrance and exit of the supercooling heat exchanger, and an inlet and a bypass circuit for the preheating heat exchanger are provided respectively. Chilled water flow regulating valve, and the capacity of the compressor is set to a capacity at which the supercooled water is obtained when the chilled water temperature at the outlet of the supercooled heat exchanger is 0 ° C. or higher. Due to the detected temperature A controller for maintaining the chilled water temperature at the outlet of the subcooling heat exchanger at a set value by adjusting the chilled water temperature at the inlet of the subcooling heat exchanger by increasing or decreasing the opening of the chilled water flow control valve. A supercooled ice heat storage device characterized in that:

[0010] A cooling water flow control valve for adjusting the flow rate of cooling water to the condenser is provided, and the opening of the chilled water flow control valve is increased or decreased to set the chilled water temperature at the outlet of the subcooling heat exchanger to a set value. When it is no longer possible to maintain the cooling water flow rate, the opening degree of the cooling water flow control valve can be controlled by the controller.

[0011]

In the present invention, since the above configuration is provided, the capacity of the compressor is set to a capacity at which the supercooled water is obtained when the chilled water temperature at the outlet of the supercooled heat exchanger is 0 ° C. or more. The chilled water temperature at the inlet of the subcooling heat exchanger is adjusted by increasing or decreasing the opening of the chilled water flow control valve in accordance with the temperature detected by both temperature detectors, and the chilled water temperature at the outlet of the subcooling heat exchanger is maintained at a set value.

When the chilled water temperature at the outlet of the supercooling heat exchanger cannot be maintained at the set value by increasing or decreasing the opening of the chilled water flow control valve, the opening of the cooling water flow control valve is controlled.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG. A temperature detector 9 for detecting the temperature of the chilled water at the inlet of the subcooling heat exchanger 3 and a temperature detector 11 for detecting the temperature of the chilled water at the outlet of the subcooling heat exchanger 3 are provided. A chilled water flow control valve 6 is provided at the inlet of the preheating heat exchanger 7, and a chilled water flow control valve 25 is provided in the bypass circuit 21. In addition, a short-circuit pipe 28 that connects the cooling water supply pipe 26 and the cooling water outflow pipe 27 of the condenser 4a is provided, and the short-circuit pipe 28 is provided with a cooling water flow control valve 29.

The detected values of the temperature detectors 9 and 11 are determined by a controller.
30 and the output of controller 30 is centrifugal chiller 2
Of the suction vane 19, the chilled water flow control valves 6, 25 and the chilled water flow control valve 29 to adjust their opening. The other configuration is the same as that of the conventional one shown in FIG. 2, and corresponding members are denoted by the same reference numerals.

When the temperature of the chilled water at the outlet of the supercooling heat exchanger 3 is 0 ° C., for example, when the heat storage operation of the ice heat storage device is started.
In the above case, the opening degree of the suction vane 19 is set so that the capacity of the centrifugal chiller 2 becomes a capacity for obtaining supercooled water.
By continuing the operation in this state, the cold water is stored in the ice storage tank.
Circulating between 10 and the supercooling heat exchanger 3 gradually cools down,
Although the temperature of the chilled water gradually decreases, the temperature of the chilled water at the inlet of the subcooling heat exchanger 3 is limited to about +0.3 to 0.8 ° C. due to restrictions for maintaining the flowability of the chilled water and preventing its freezing. , Cannot be reduced below this.

Therefore, the degree of opening of the chilled water flow control valves 6, 25 is increased or decreased according to the temperature detected by the temperature detector 9, and the chilled water temperature at the inlet of the subcooled heat exchanger 3 is adjusted. Control is performed so that the chilled water temperature at the outlet 3 becomes a set value. When it becomes impossible to maintain the chilled water temperature at the outlet of the subcooling heat exchanger 3 at the set value by controlling the chilled water flow regulating valves 6 and 25, the opening degree of the cooling water flow regulating valve 29 is adjusted to condense. By changing the condensing pressure and temperature of the refrigerant in the heat exchanger 4, the sudden change of the evaporating pressure and temperature of the refrigerant in the supercooling heat exchanger 3 is avoided, and the chilled water temperature at the outlet of the supercooling heat exchanger 3 is maintained at a set value.

[0017]

According to the present invention, the capacity of the compressor is set to a capacity at which the supercooled water can be obtained when the temperature of the chilled water at the outlet of the supercooled heat exchanger is 0 ° C. or higher. The cooling water temperature at the inlet of the supercooling heat exchanger is adjusted by increasing or decreasing the opening of the chilled water flow control valve according to the detected temperature, and the chilled water temperature at the outlet of the supercooling heat exchanger is maintained at the set value. Since it is possible to avoid a sudden change in the evaporation pressure and temperature of the refrigerant in the heat exchanger, it is possible to prevent a decrease in the flowability of the cold water and freezing in the pipe.

When the chilled water temperature at the outlet of the subcooling heat exchanger cannot be maintained at the set value by increasing or decreasing the opening of the chilled water flow control valve, the opening of the cooling water flow control valve is controlled,
By adjusting the flow rate of the cooling water to the condenser, the temperature of the cooling water at the outlet of the supercooling heat exchanger can be maintained at the set value.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of the present invention.

FIG. 2 is a system diagram of a conventional device.

[Explanation of symbols]

 2 Variable capacity compressor 4 Condenser 3 Subcooling heat exchanger 10 Ice storage tank 7 Preheating heat exchanger 21 Bypass circuit 9, 11 Temperature detector 6, 25 Chilled water flow control valve 30 Controller 29 Cooled water flow control valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F24F 5/00 F25C 1/00

Claims (2)

(57) [Claims] The refrigerant is circulated in the order of a variable capacity compressor, a condenser, and a supercooling heat exchanger, and chilled water supplied from an ice heat storage tank through a preheating heat exchanger and a bypass circuit thereof is subjected to the supercooling heat exchange. After cooling to a supercooled state with a heat exchanger, the supercooled ice heat storage device that generates ice and stores heat by releasing the supercooled state in the ice heat storage tank, the cold water temperature at the entrance and exit of the supercooled heat exchanger. A temperature detector for detecting each, a chilled water flow control valve provided at each of the inlet and the bypass circuit of the preheating heat exchanger, and supercooled water when the chilled water temperature at the outlet of the supercooled heat exchanger is 0 ° C or more. The capacity of the compressor is set to the obtained capacity, and in this state, the opening degree of the chilled water flow control valve is increased or decreased according to the temperature detected by the two temperature detectors to increase the chilled water temperature at the inlet of the subcooling heat exchanger. By adjusting above A supercooled ice heat storage device comprising: a controller for maintaining a temperature of a chilled water at an outlet of a supercooled heat exchanger at a set value. 2. A cooling water flow control valve for adjusting the flow rate of cooling water to the condenser is provided, and the temperature of the cooling water at the outlet of the supercooling heat exchanger is reduced by increasing or decreasing the opening of the cooling water flow control valve. 2. The supercooled ice heat storage device according to claim 1, wherein the controller controls the opening degree of the cooling water flow control valve when the set value cannot be maintained.